import math
x1, y1, x2, y2 = map(float, input().split())
a = x2 - x1
b = y2 - y1
print(math.sqrt(a**2 + b**2)) import math math x1, y1, x2, y2 = map(float, input().split()) x1 map(float, input().split()) map float input().split() ().split () input split y1 x2 y2 a = x2 - x1 a x2 - x1 x2 x1 b = y2 - y1 b y2 - y1 y2 y1 print(math.sqrt(a**2 + b**2)) print math.sqrt(a**2 + b**2) math.sqrt math sqrt a**2 + b**2 a**2 a 2 b**2 b 2 a = x2 - x1 x2 - x1 a x1, y1, x2, y2 = map(float, input().split()) map(float, input().split()) x1 y1, x2, y2 = map(float, input().split()) map(float, input().split()) y1 x2, y2 = map(float, input().split()) map(float, input().split()) x2 b = y2 - y1 y2 - y1 b y2 = map(float, input().split()) map(float, input().split()) y2
import math
x1, y1, x2, y2 = map(float, input().split())
a = x2 - x1
b = y2 - y1
print(math.sqrt(a**2 + b**2))
